Spectrally encoded endoscopy (“SEE”) is a technique that uses wavelength to encode spatial information on a sample, thereby allowing high-resolution imaging to be conducted through small diameter endoscopic probes. SEE can be accomplished using a quasimonochromatic or broad bandwidth light input into a single optical fiber. At the distal end of the fiber, a diffractive or dispersive optic disperses the light across the sample, which is reflected and returns back through the optic and optical fiber. Light from the optical fiber is detected by a wavelength detecting apparatus, such as a spectrometer. By detecting the light intensity as a function of wavelength, the image may be reconstructed. SEE techniques have been described in, e.g., U.S. Pat. Nos. 7,843,572, 8,145,018, 6,341,036, 7,796,270 and U.S. Patent Publication Nos. 2008/0013960 and 2011/0237892, the entire contents of which are herein incorporated by reference.
Conventional endoscopy uses RGB color information as cues to diagnosis. By using wavelength information to encode spatial location, SEE images utilize much of the color information to encode spatial location and therefore important color information may be lost. Previously, methods for conducting color imaging in an SEE probe have been proposed. For example, color SEE imaging in a bench top setup has been described (See, e.g., Optics Express, 17(17), 15239-15247; 2009). In this bench top setup, three light beams, each with one of the red, green, and blue spectral bands, were used. These light beams were incident on the grating at different angles, which resulted in same diffraction angle for all three spectral bands. Therefore, each point on the tissue was illuminated with three spectral bands. While this method showed a feasibility of conducting color SEE imaging, implementing this method into a miniature SEE probe has many technological challenges. Three fibers need to be precisely aligned and assembled with the miniature lens. These three fibers generally make the scanning on a SEE probe challenging. In a different approach, color SEE imaging was demonstrated using a single illumination beam (see, e.g., Optics Express, 19(7), 6913-6922; 2011). In this method, each point of the specimen was illuminated with single wavelength, but the specimen was translated relative to the SEE set up. Therefore, each point of the specimen was examined by multiple wavelengths, and the spectral information was used to recover color images of the specimen. This conventional method, however, uses a precise translation of the specimen in a controlled manner, which is not feasible in endoscopic imaging applications.
Accordingly, there may be a need to address and/or overcome at least some of the deficiencies described herein above.